Monitoring of seawater immersion degradation in glass fibre reinforced polymer composites using quantum dots

In this paper, a simple and innovative method is proposed to monitor the effects of seawater ageing in glass fibre reinforced polymer (GFRP) composites using quantum dots (QDs). The cadmium sulfide (CdS) QDs modified with 3-(trimethoxysilyl)-1-propanethiol (MPS) were firstly synthesized, and then the modified CdS QDs were labeled on the glass fibre by chemical bond. GFRP composites with QDs at the interface between the fibre and matrix were obtained. The sigle-fibre-fragment tests of specimens were done to verify the modified CdS QDs did not affect the interfacial bonding of the matrix and fiber. The effects of seawater ageing on the adhesion behaviour between the fibre and the matrix of QD/GFRP hybrids were investigated based on confocal fluorescence microscopy images. After 6 months of immersion in seawater, the glass transition temperature (Tg), tensile strength, and flexural strength of specimens decreased 2.5%, 13.8%, and 9.8%, respectively. Furthermore, the thermal and mechanical properties of specimens can be calculated by the fluorescence intensity quantificationally.